The invention relates to an apparatus for regulating the feed thickness of feed material which is fed into a belt press machine.
Belt press machines are used in a variety of applications, including processing sludges and separating juice and pulp from fruit. The machine is basically operated on the principle of pressing feed material such as sludge or fruit between two moving belts. The pressing is accomplished by moving the belts over a series of rollers and sequentially narrowing the spacing between the belts so as to press the feed material therebetween. During the pressing operation, water or juice is forced outward through the belts or beyond their edges and is collected by suitable means. At the end of the pressing operation, the partially de-watered feed material is expelled from the belts.
The pair of belts used for the pressing operation are each moved over separate drive and idler rollers in an endless loop. Typically, feed material is deposited on one of the belts at a section where the belt is horizontally aligned and the deposited feed material is moved along by the one belt and brought into contact with the opposing belt. In one known belt press, described in U.S. Pat. No. 3,984,329 to Wenzel, the feed material is brought into contact with the opposing belt at a section where both belts are sharply vertically inclined. In this belt press, the feed material is initially squeezed between the belts as it slides downward between the vertically inclined section of the belt in a chute-like manner. In another known belt press, the feed material is brought into contact with the opposing belt at a section of the belt press where the two opposing belts are approximately horizontal
It is advantageous to have the thickness of the feed material as uniform as possible during the time that the feed material is initially pressed between the opposing belts. Differences in the rate of travel of each belt can arise when feed material of varying thickness is initially pressed. This differential rate of travel of the two belts leads to such undesirable consequences as one of the belts folding on itself, thereby necessitating shutdown of the belt press operation to unfold the belt.
To ensure that the thickness of the feed material is as uniform as possible, a squeeze plate apparatus has been used to squeeze the incoming feed material immediately before it is pressed between the opposing belts. The squeeze plate apparatus has a smooth surface plate having a width at least equal to the width of the cake which is almost as wide as the belt. The plate is mountable between or around the belts at the section of the belt press where the feed material is first being brought into contact with the second opposing belt by the first opposing belt. The squeeze plate squeezes the material against one of the belts so as to reduce the feed material to a generally uniform thickness before it is squeezed by the two opposing belts. The squeeze plate is adjustable in a direction transverse to the direction of movement of the feed material so that it can be spaced from the associated belt at various distances, depending upon the desired degree of squeezing of the feed material which is desired.
In one known squeeze plate apparatus, the squeeze plate is suspended above the underlying belt by a number of bolts spaced around the periphery of the squeeze plate. To adjust the squeeze plate, each bolt must be appropriately rotated. If careful attention is not paid during the rotation of the individual bolts, the surface of the squeeze plate will not be parallel to the underlying belt, resulting in feed material of varying thickness as the feed material passes beyond the squeeze plate.
It would be advantageous to have a squeeze plate apparatus which can be easily and rapidly adjusted to vary the degree of squeezing action. Furthermore, it would be advantageous to have a squeeze plate apparatus which can be adjusted from one side of the belt press. Also, it would be advantageous to have a squeeze plate apparatus which can be adjusted without interrupting the operation of the belt press. A further advantage would be an improved squeeze plate apparatus which can be easily adjusted to several positions while ensuring that at each position the smooth surface of the plate is uniformly spaced from the underlying belt.